Introduction Gordon Clubb, Ryan Scrivens and Md. Didarul Islam Section 1: Academic Perspectives Chapter 1: Understanding the Effectiveness of Formers: Contexts and Measurements Daniel Koehler Chapter 2: "Informed Informants": An Empirical Exploration of Using Formers within P/CVE Work in the UK Suraj Lakhani Chapter 3: Being a Former, Becoming a Mentor, and the Value of Using Formers in the Swedish Exit Program Tina Wilchen Christensen Chapter 4: Moral Injury, Moral Blindness, Political Non-Repentance: Former ETA Members and Prevention and Countering Violent Extremism Rogelio Alonso Chapter 5: Former Extremists in North American Research Ryan Scrivens, Steven Windisch, and Pete Simi Chapter 6: "Informative, Shocking, Entertaining": Two Decades of Talks by Former Extremists in German Schools Maria Walsh and Antje Gansewig Chapter 7: The Role of Former Northern Irish Combatants in Building Peace and Preventing Violence: Community and Combatant Perspectives Neil Ferguson and Patrick Flack Chapter 8: Missed Potential for Former Fighters' Involvement in Conflict Prevention: The Case of Burundi Guðrún Sif Friðriksdóttir Chapter 9: Do Former Child Soldiers Have a Role in Peacebuilding in Colombia? Patrícia Nabuco Martuscelli and Rafael Duarte Villa Section 2: Practitioner Perspectives Chapter 10: Formers in Lebanon Christina Foerch and Julie M. Norman Chapter 11: Transitioning from Former Violent Extremist to Exit Peer Specialist Katharina Meredith and Robert Örell Chapter 12: Collaboration with Former Extremists Lynn Davies Chapter 13: How I Understand the Role of Former as a Former Turned Activist Mubin Shaikh Chapter 14: Former Extremists as Peer Mentors in P/CVE Sara Winegar Budge Chapter 15: Life after Hate Brad Galloway Chapter 16: From Former to Practitioner Chris Buckley Chapter 17: The Ethical Imperatives of Engaging Formers in P/CVE Efforts Ross Frenett Conclusion: Norms and Standards for Formers Engaging in Violence Prevention Gordon Clubb, Ryan Scrivens and Md. Didarul Islam.